Biomechanical Modeling and Evaluation of Buttocks Automatic Assisted Repositioning in Bedridden Patients

Area of Science:

• Biomechanics
• Medical Engineering
• Computational Modeling

Background:

• Pressure ulcers (PUs) are a major care challenge for bedridden patients.
• Automated tilt nursing beds offer a potential solution, but lack models for deep tissue response analysis.
• Optimizing tilt angles is crucial for effective automatic repositioning in long-term care.

Purpose of the Study:

• To develop a novel computational model for simulating automatic assisted repositioning.
• To analyze deep tissue biomechanical responses during repositioning.
• To optimize tilt angles for effective load offloading and pressure relief.

Main Methods:

• Developed a computational model integrating buttocks and mattress for repositioning simulation.
• Employed inverse modeling for 3D buttocks reconstruction and nodal equivalence for mesh simplification.
• Utilized Response Surface Methodology (RSM) for soft tissue parameter optimization.
• Conducted finite element (FE) analysis to evaluate biomechanical responses and optimize strategies.

Main Results:

• Model validation showed low deformation error (6.93 ± 7.41 mm) and acceptable interface pressure differences (within 22.4%).
• Simulations indicated a 30° turning angle reduced total soft tissue strain by 20%.
• Peak equivalent stress decreased by over 20% at critical tissue interfaces with a 30° tilt.

Conclusions:

• The developed computational model is effective and bio-fidelic for simulating assisted repositioning.
• A 30° turning angle is optimal for reducing pressure concentration and deep tissue stress.
• Findings can inform the design of automatic assisted repositioning systems for improved patient outcomes.